99 ML320 no acceleration and bogs
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99 ML320
99 ML320 no acceleration and bogs
I hope someone can help me here because I'm stumped. I was driving on the freeway and it stopped accelerating. The highest I could reach was 40mph so I drove it back home. Scanned it and it read 2 of the 02 sensors were bad, cylinders 1-3 misfire and a random multiple misfire detected. Replaced the 2 02 sensors, air filter,spark plugs and changed the air valve. measured the gas pressure at 50+ lbs. There is a rattle in the catalytic converter. After replacing these parts, started it up and still doing the same thing minus the 02 sensor codes. I'm not sure what could be the issue. Any suggestions or help would be greatly appreciated.
MBWorld Fanatic!
Joined: Oct 2011
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From: Bronx, N.Y.
2002 ML 320 & 2006 ML500
Once there is a rattle in the cat. converter, broken pieces cause exhaust blockage creating back pressure, which in turn causes misfires. Once too many misfires are recorded by the eng. computer, it will shut down those cylinders or the entire bank, cyls.1,2 & 3.
Once that happens the O2 sensors have no exhaust or not enough exhaust to read, thereby showing faulty.
Do not replace the O2 sensors until you have replaced the cat. You must also check to see the the broken pieces have not made their way to the secondary cat.
Once that happens the O2 sensors have no exhaust or not enough exhaust to read, thereby showing faulty.
Do not replace the O2 sensors until you have replaced the cat. You must also check to see the the broken pieces have not made their way to the secondary cat.
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Joined: Sep 2020
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1998 ml320
Solved
I took the forward 02 sensor on the passenger side out, because my car was doing the exact same thing, the car ran fine, deleted all cats, no issues, still have the 02 sensors in all 4, I changed all plugs, all wires, and coils it did not fix anything, also checked fuel pressure, finally no check engine light 1000 miles later and counting.
